EVAPCO AT Series Operation And Maintenance Instructions

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Operation and Maintenance Instructions
unit so as not to transmit additional loads to the equipment as a result of seismic or wind forces.
Initial and Seasonal Start-Up Checklist
General
1. Verify that the overall installation reflects the requirements of the installation guidelines found in EVAPCO Bulletin 311 –
Equipment Layout Manual.
2. For multi-speed fan motors, verify that 30 second or greater time delays are provided for speed changes when switching from
high to low speed. Also check to see if interlocks are provided to prevent simultaneously energizing high and low speed and
confirm both speeds operate in the same direction.
3. Verify all safety interlocks work properly.
4. For units operating with a variable frequency drive, make certain that minimum speed requirements have been set. Check with
VFD manufacturer for recommended minimum speeds and recommendations on locking out resonance frequencies. See “Fan
System Capacity Control” section for more information.
5. Verify that the sensor used for fan sequencing and by-pass valve control is located downstream of the point where the by-pass
water mixes with the condenser supply water, if applicable.
6. Verify that a water treatment plan has been implemented including passivation of galvanized steel units. See “Water
Treatment” section for more details.
7. For units subject to freezing climates, high humidity climates, or idle periods lasting 24 hours or more, motor space heaters (if
equipped) should be energized. Alternatively, fan motors may be energized for 10 minutes, twice daily, to drive any moisture
condensation out of the motor windings.
8. If the unit is going to sit idle for an extended period of time, follow all manufacturersʼ fan motor and pump instructions for long
term storage. Plastic sheets or tarps should never be used to protect a unit during storage. This practice can trap heat inside
the unit, and could potentially cause damage to plastic components. See your local EVAPCO representative for additional
information on unit storage.
BEFORE BEGINNING ANY MAINTENANCE, BE CERTAIN THAT THE POWER IS TURNED OFF
AND THE UNIT IS PROPERLY LOCKED AND TAGGED OUT!
Initial and Seasonal Start-Up
1. Clean and remove any debris, such as leaves and dirt from the air inlets.
2. Flush the cold water basin (with the strainer screens in place) to remove any sediment or dirt.
3. Remove the strainer screen, clean and reinstall.
4. Check mechanical float valve to verify it operates freely.
5. Inspect water distribution system nozzles and clean as required. Check for proper orientation. (This is not required at initial
start-up. The nozzles are clean and set at the factory).
6. Check to ensure drift eliminators are securely in place.
7. Adjust fan belt tension as required.
8. Lubricate fan shaft bearings prior to seasonal start-up.
9. Turn the fan(s) by hand to insure it turns freely without obstructions.
10. Visually inspect the fan blades. Blade clearance should be approximately 3/8” (1/4” minimum) from tip of blade to the fan cowl.
The fan blades should be securely tightened to the fan hub.
11. If any stagnant water remains in the system including “dead legs” in the piping, the unit must be disinfected prior to the fans
being energized. Please refer to Ashrae Guideline 12-2000 and CTI Guideline WTP-148 for more information.
12. Fill the cold water basin manually up to the overflow connection.
After the unit has been energized, check the following:
1. Adjust mechanical float valve as required to the proper water level.
2. Unit basin should be filled to the proper operating level. See “Recirculating Water System – Operating Levels” section for more
details.
3. Verify fan is rotating in proper direction.
4. Measure voltage and current on all three power leads. The current should not exceed the motor nameplate full load amp rating
taking the service factor into account.
5. Adjust bleed valve to proper flow rate. Maximum bleed off is 3 US GPM per 100 tons. Consult your qualified water treatment
person to fine tune the minimum bleed necessary.
6. Refer to the fan motor manufacturerʼs maintenance and long term storage instructions for more detailed information. Motors
should be serviced in accordance with manufacturerʼs instructions.

EVAPCO AT Series Specifications

General

Brand	EVAPCO
Model	AT Series
Category	Accessories
Language	English